Power transmission chains composed of pivotably connected sets of interleaved links are known in the art. In one type of chain, commonly known as a "Silent" chain, each of the links which drivingly engage the teeth of a sprocket is defined by a pair of toes, each toe being at the juncture of an inside flank and an outside flank. The inside flanks are joined by a crotch. The backs of these links are generally arcuate or curved.
It has been suggested to construct a chain with some set of links all having inside flanks which drivingly engage the sprocket teeth, and other set of links all having outside flanks which drivingly engage the sprocket teeth. The uniform sets of links (that is, all inside flank engagement or all outside flanks engagement) may be mixed in a regular or random pattern. When all the links in each rank or set of links are uniform, there is a reduction in the apparent noise level or psychological distraction produced by operation of such a chain. Such a chain is described and claimed in our co-pending application, Ser. No. 150,370, filed May 16, 1980.
However, if each set of links is not uniform, the amount of noise reduction is not as great. That is, if one inside flank engagement link is positioned with a plurality of outside flank engagement links to form one set of links, there is a noticeable increase in the noise level when the chain operates. The assembly of uniform ranks or sets of links has proved difficult because the physical difference between the inside flank engagement and outside flank engagement links are physically and visually very small, and do not admit of ready detection by automatic sorting apparatus.
It is therefore a primary object of the present invention is to provide a power transmission chain of the type generally described in the above-identified application, but in which each link has some physical characteristic (other than its flank profile) which readily identifies the links as either an inside flank or outside flank engagement link.